The present invention relates to a hoisting device for big loads, comprising at least one hoisting mast, a foot arranged on the underside and hoisting means connected at least to the top, wherein the hoisting device is assembled from mast parts which are mutually connectable by means of connecting means and the largest of which has dimensions which do not exceed those of a usual container, and wherein each mast part is constructed as a framework structure consisting of angle bars and cross bars mutually connecting the angle bars.
The present invention relates particularly to hoisting devices which can handle, hoist and displace very large prefabricated modules such as chemical processing installations, offshore installations, windmills and so on, often of more than 1000 tons, to a great height in the order of magnitude of 120 m.
The projects on which these installations can be deployed are spread throughout the world. It will therefore be apparent that in choosing the dimensions of the components of the hoisting device account must be taken of transport to and from the location where the project is being carried out. The design of ships for transport by sea and inland waterways and developments in overland transport using trucks and trains are determined more and more by the use of sea-cargo containers. The locations for transhipment of goods are likewise being adapted increasingly for handling of these containers.
In order therefore to make the mobilization of lifting and hoisting material attractive in view of the described trends in the field of transport and to keep the associated costs acceptable, mast parts have been sought which embody the great strength and stiffness (bending and buckling) necessary for the hoisting device within the typical dimensions of sea-cargo containers and which can also be coupled in simple manner to form the desired mast length. Such a hoisting device is known from the international patent application no. PCT/NL97/00099.
The object of the present invention is to improve the hoisting device known from the prior art and to design mast parts of the greatest possible strength and stiffness within the dimensions of typical sea-cargo containers.
This object is achieved in that the angle bars consist of two parts with a set-square-shaped cross-section of different dimensions, wherein the outer ends of the legs of the smaller lie against the legs of the larger and the larger part lies on the outer periphery of the mast part.
The profile of the angle bars provides, relative to the usually applied profiles, an optimum use of the material within the dimensions defined by the standard container, also with a view to the other requirements relating to fixing of framework rods and the coupling method. The fixing surface between the angle bars and the cross bars is in fact flat, so that the cross bars can be arranged directly onto the angle bars without any modification. This design also provides the greatest possible available space inside the framework which enables optimal utilization of the mast part in the container application during transport.
The corners of the parts of the angle bars are preferably rounded. The parts of the angle bars are hereby easier to manufacture. In addition, no sharp edges are present on the mast parts.
For coupling of the mast parts the connecting means are slidably received in close-fitting manner in the angle bars, which means comprise two identical plate pieces and a filler body arranged therebetween. At least two holes are herein arranged in each plate piece and holes are arranged on the outer ends of the angle bars of each mast part, wherein the holes of the plate pieces lie in one line in each case with two holes of two mutually abutting mast parts for receiving a pin. The connecting means provide centering of the mast parts and absorption of the tensile and transverse forces (bending load) between the mast parts when the hoisting device is carried upward.
During moving upward of the hoisting device the maximum shearing force is to be found on the contact plane of the mast parts. In preference the filler body is therefore arranged between the holes of the plate pieces so that this filler body, which is situated on the contact plane of the mast parts, can absorb the maximum shearing force.
The centre distance between the holes of the plate pieces is such that the end surfaces of the mast parts abut one another. Once the crane has been raised, the mast parts lie mutually abutting and the forces occurring as a result of hoisting a load are for the most part transmitted directly from the one mast part to the other and the connecting means are almost not loaded.
In order to make the mast part suitable for transport, an auxiliary frame is arranged on each end surface of the mast part, which frame is provided with coupling means corresponding with those of the usual container, wherein the dimension between the coupling means on the one and on the other end surface of the mast part and the dimension between the coupling means on one side of the mast part mutually correspond with those of a usual container.